a) (2345-45)+2345

= 2300 + 2345

= 4645

b) (-2010)-(119-2010)

= -2010-119+2010

= (2010-2010)-199

= -199 

c) (18+29)+(158-18-29)

= 18+29+158-18-29

= (18-18)+(29-29)+158

= 158

d) 126+(-20)+2004+(-106)

= 126 -20 + 2004 - 106

= (126-20-106) +2004

= 2004

e) (-199)+(-200)+(-201)

= -(199+200+201)

= -600

g) 217+ [43+(-217)+(-23)]

= 217+ 43 - 217 + 23

= (217-217)+(43-23)

= 20

-Học tốt-

a: \(\left(2345+45\right)-2345\)

\(=2345+45-2345\)

\(=45+\left(2345-2345\right)\)

=45+0

=45

b: \(\left(-2010\right)-\left(119-2010\right)\)

\(=-2010-119+2010\)

\(=\left(-2010+2010\right)-119\)

=0-119

=-119

c: \(\left(18+29\right)+\left(158-18-29\right)\)

\(=18+29+158-18-29\)

\(=158+\left(18-18\right)+\left(29-29\right)\)

=158+0+0

=158

d: \(126+\left(-20\right)+2004+\left(-106\right)\)

\(=126-20+2004-106\)

\(=\left(126-20-106\right)+2004\)

=0+2004

=2004

e: \(\left(-199\right)+\left(-200\right)+\left(201\right)\)

\(=-199-200+201\)

\(=-199+\left(201-200\right)\)

=-199+1

=-198

f: \(99+\left(-100\right)+101\)

\(=\left(99+101\right)-100\)

=200-100

=100

g: \(217+\left[43+\left(-217\right)+\left(-23\right)\right]\)

\(=217+43-217-23\)

\(=\left(217-217\right)+\left(43-23\right)\)

=0+20

=20

a) 126+(−20)+2004+(−106)126+(−20)+2004+(−106)

=2004+126+[(−20)+(−106)]=2004+126+[(−20)+(−106)]

=2004+126+[−(20+106)]=2004+126+[−(20+106)]

=2004+126+(−126)=2004+126+(−126)

=2004+[126+(−126)]=2004+0=2004=2004+[126+(−126)]=2004+0=2004.

b) (−199)+(−200)+(−201)=−(199+200+201)(−199)+(−200)+(−201)=−(199+200+201)

=−(199+201+200)=−[(199+201)+200]=−(199+201+200)=−[(199+201)+200]

=−(400+200)=−600=−(400+200)=−600.

Gọi a là số cần tìm 

=> a+1 chia hết cho 5;7 và 9

Mà a nhỏ nhất

Nên a+1 nhỏ nhất

=>BCNN(5;7:9)=a+1

=>a+1=5.7.9=315

=> a=314

Vậy số cần tìm là 314

Bài 3: Ta có

567⁴⁰⁴⁰=(567⁴)¹⁰¹⁰=......1¹⁰¹⁰=.............1

201²⁰¹³=............1

=>567⁴⁰⁴⁰-201²⁰¹³=.............1-................1=.................0 chia hết cho 10(đpcm)

Vậy 567^{4040 -} 201²⁰¹³ chia hết cho 10

ghi hẳn ra giúp mình với nhé

d ) \(\left|-18\right|:\left(14-11^2\right)\)

      \(=18:\left(14-121\right)\)

      \(=18:-107\)

         \(=-\frac{18}{107}\)

e ) \(\left(-25\right)+1945+\left(-75\right)+\left(-1945\right)\)

         \(=\left[\left(-25\right)+\left(-75\right)\right]+\left[1945+\left(-1945\right)\right]\)

          \(=-100+0\)

            \(-100\)

f ) \(217+\left[43+\left(-217\right)+\left(-23\right)\right]\)

  \(=217+43+\left(-217\right)+\left(-23\right)\)

\(=\left[217+\left(-217\right)\right]+\left[43+\left(-23\right)\right]\)

\(=0+20\)

\(=20\)

Chúc bạn học tốt !!!

a) 126 + (-20) + 2004 + (-106)

 = 106 + 1898

 =   2004

b) (-199) + (-200) + (-201)

 =  (-399) + (-201)

=  -600